Environmental Issues in California: 8 Biggest Problems and What Is Being Done

The biggest environmental issues in California are wildfires, drought and a shrinking snowpack, groundwater overdraft and sinking land, smog and soot, extreme heat, rising seas and eroding beaches, the collapse of salmon runs and thousands of idle oil and gas wells near homes. Several of these environmental problems in California, including heat, snowpack loss, wildfire and rising seas, are tracked by the state as indicators of climate change (OEHHA).

California had 39.5 million residents on July 1, 2025, according to the California Department of Finance. The state emitted 360.4 million metric tons of greenhouse gases (CO2e) in 2023, 3.0% less than in 2022 and below the 1990-level limit of 431 million tons, according to the California Air Resources Board (CARB). Under AB 1279, the state’s Scoping Plan aims for carbon neutrality and an 85% cut below 1990 levels by 2045. Below are the eight main problems with the latest official figures, a summary table, what is being done and what you can do.

Top 8 Environmental Issues in California

1. Wildfires

In 2025, California recorded 8,232 wildfires that burned 507,817 acres (about 205,500 hectares), destroyed 16,627 structures and killed 31 people (a preliminary figure pending coroner confirmation), according to CAL FIRE. Most of the damage came from two fires that started on January 7, 2025, in Los Angeles County. The Palisades Fire burned 23,448 acres, destroyed 6,837 structures and killed 12 people; the Eaton Fire burned 14,021 acres, destroyed 9,414 structures and killed 19, according to a Los Angeles County fact sheet.

The 2026 season has been calmer so far: 6,324 wildfires, 339,451 acres and 177 structures destroyed as of late October (CAL FIRE). The long-term trend is clear, though. All but two of California’s largest wildfires by acreage have occurred since 2000, and an estimated 243 million trees died on the state’s forest lands from 2010 to 2024, according to the state’s 2026 Indicators of Climate Change in California report (OEHHA).

2. Drought and a Shrinking Snowpack

The Sierra Nevada snowpack supplies about 30% of California’s water needs in an average year. On April 1, 2026, after a record-hot, dry March, the statewide snowpack was just 18% of average for the date, and the Northern Sierra was at 6%, according to the Department of Water Resources (DWR). Water year 2026 ranked among the warmest 10% of years since 1896 across nearly all of the California-Nevada region, and most snow monitoring stations melted out 30–60 days early, according to Drought.gov.

Wet months early in the water year kept major reservoirs near or above their historical averages, the same update says. As of October 27, 2026, 18.4% of the state was in moderate drought or worse, affecting about 1.5 million residents, and another 53.8% was abnormally dry (U.S. Drought Monitor via Drought.gov). The longer trend points one way: spring snowmelt runoff has fallen 20% on the Sacramento River over the past century, and Sierra Nevada glaciers have lost about 75% of their area since 1903 (OEHHA).

3. Groundwater Overdraft and Sinking Land

Groundwater meets about 40% of California’s water demand in average years and nearly 60% in dry years, and more than 32 million Californians (about 82%) rely on it, according to DWR’s Bulletin 118 – Update 2025. Agriculture uses about 79% of the groundwater pumped.

Excessive groundwater pumping is one of the causes of land subsidence, which has permanently damaged canals, pipelines, roads and homes, according to DWR. About 4,000 square miles (10,400 km²) subsided by more than half a foot (15 cm) in the past five years, and hundreds of wells went dry during the 2020–2022 drought, according to Bulletin 118. From 2014 to 2024, about 20% of monitored wells dropped 5 feet (1.5 m) or more, while 41% rose by that much. Under the Sustainable Groundwater Management Act (SGMA), local agencies have planned more than 1,500 projects, and DWR has allocated over $500 million in planning and implementation grants.

4. Smog and Soot

California’s air is cleaner than it was decades ago, but it still ranks poorly in the American Lung Association’s State of the Air 2026, which covers 2022–2024 data. Los Angeles-Long Beach ranked as the most ozone-polluted U.S. metro area, with an average of 159.2 unhealthy ozone days a year, followed by Visalia and Bakersfield. Bakersfield ranked most polluted for year-round particle pollution, and Fresno was fourth. More than eight in ten Californians (82%) live in counties affected by unhealthy air, the ALA says.

Vehicles are also the state’s biggest climate polluter: transportation produced 38.0% of California’s greenhouse gas emissions in 2024, the largest share of any sector, according to CARB.

5. Extreme Heat

California’s average annual temperature has risen about 2.6°F (1.4°C) since records began in 1895, and 2024 and 2025 were the sixth- and seventh-warmest years on record, according to OEHHA. Reported heat-related deaths in 2024 were nearly triple the number in 2000, according to OEHHA’s heat-illness indicator.

Official counts understate the toll. For the September 2022 heat wave, the state estimated 395 excess deaths from all causes, but only 20 were coded as heat-related on death certificates, the same indicator says. Outdoor workers face the highest risk: Hispanic workers account for 45% of heat-related emergency room visits, and low-income workers are five times as likely as high-income workers to need one (OEHHA).

6. Sea Level Rise and Coastal Erosion

Sea level along the California coast is now rising at three times the 20th-century rate (OEHHA). The Ocean Protection Council’s 2024 Sea Level Rise Guidance, which state and local agencies use for planning, projects an average of 0.8 feet (24 cm) of rise by 2050 and 1.6–3.1 feet (0.5–0.9 m) by 2100, with higher amounts not ruled out.

Beaches are especially exposed. Research announced by the U.S. Geological Survey in 2023 estimates that 24% to 75% of California’s beaches could be completely eroded by 2100 under 1 to 3 meters (3.3 to 9.8 feet) of sea level rise with no interventions, which would also threaten coastal infrastructure and habitats (USGS).

7. Salmon Collapse and Warming Waters

California’s commercial ocean salmon fishery last opened in 2022, according to the Pacific Fishery Management Council (PFMC). The 2023–2025 shutdown was the longest multi-year commercial closure in the state’s history, according to the fisheries research firm FISHBIO, which blames drought, high water temperatures, nonnative species and poor habitat.

The runs have started to recover. Sacramento River fall Chinook escapement (adults returning to spawn) reached 164,763 in 2025, and the 2026 ocean abundance forecast was 392,349 fish, according to the PFMC’s 2026 preseason report. That return was 65% higher than in 2024, FISHBIO calculates. For 2026, the PFMC allowed limited commercial openers between Point Arena and Pigeon Point. In May 2026, the Fish and Game Commission reopened salmon fishing on the Klamath, Trinity and Sacramento rivers, crediting hatchery production, habitat restoration, good water years, dam removals and the closures themselves (California Natural Resources Agency). The ocean is still a risk: record marine heat waves occurred off California in six of the seven years from 2019 to 2025 (OEHHA).

8. Idle Oil and Gas Wells Near Homes

California has about 32,000 oil and gas wells classified as idle, meaning they have not produced or injected for at least 24 consecutive months, according to the state’s Geologic Energy Management Division (CalGEM). Wells that are not properly sealed can let oil, gas or other contaminants migrate into drinking water or to the surface, CalGEM says. According to Times of San Diego, a 2020 California Energy Commission study found that 65% of surveyed idle wells were leaking methane, and a Center for Biological Diversity report released in February 2026 counted more than 4,000 idle wells within 3,200 feet of sensitive sites such as schools, parks and residential care facilities.

Under a 2022 law, SB 1137, CalGEM stopped approving new well permits in 3,200-foot (975 m) health protection zones around homes, schools, hospitals and other sensitive locations (CalGEM). Before working in those zones, operators must notify tenants and property owners within 3,200 feet of the wellhead and offer to test their water. The rules have been in effect since June 2024, when a referendum against the law was withdrawn (CalGEM notice).

California’s Environmental Issues at a Glance

What Is Being Done

• Cap-and-Invest. On September 19, 2025, Governor Newsom signed AB 1207, which extends the state’s carbon market, renamed Cap-and-Invest, through 2045, along with the companion bill SB 840; CARB then proposed amendments to the regulation to match (CARB).
• Clean electricity (SB 100). SB 100 sets targets of 60% renewable and zero-carbon retail electricity by 2030 and 100% by 2045. In 2024, 67% of retail sales came from zero-carbon sources, including 45.2% from certified renewables (California Energy Commission), and battery storage capacity reached 21,112 MW as of August 2026 (CEC).
• Clean cars, in court. In 2025, Congress used the Congressional Review Act to revoke the federal waivers for California’s Advanced Clean Cars II, Advanced Clean Trucks and Omnibus rules. California and other states sued on June 12, 2025, arguing that waivers are not subject to that law (California Attorney General). Meanwhile, CARB readopted its earlier Advanced Clean Cars I standards and began work on a new program called Drive Forward, according to the law firm Alston & Bird. In a separate case, on September 2, 2026, a federal district court in Washington, D.C., granted California a preliminary injunction against EPA’s reclassification of the waivers as rules subject to the Congressional Review Act (court opinion). EPA appealed to the D.C. Circuit on September 14, 2026 (DTN).
• Climate bond. Voters approved Proposition 4, a $10 billion climate bond, in November 2024. It includes $3.8 billion for drinking water, drought and floods, $1.5 billion for wildfire and forest resilience, $1.2 billion for coastal resilience and $450 million for extreme heat; $3.47 billion was appropriated in 2025–26 (Legislative Analyst’s Office).
• 30×30 conservation. As of September 2026, California had conserved 27.1% of its lands and 21.9% of its coastal waters toward its goal of 30% by 2030 (Office of the Governor).
• Less plastic (SB 54). The 2022 law requires a 25% cut in covered plastic packaging and a 65% recycling rate for it by 2032, and covered packaging must be recyclable or compostable by then (CalRecycle).

What You Can Do

• Create defensible space. State law requires defensible space up to 100 feet around your home in fire-prone areas. CAL FIRE also recommends an ember-resistant Zone 0 within 5 feet of the house, which is not yet legally required (ReadyForWildfire). Local rules may be stricter.
• Respond to Flex Alerts. During heat waves, the grid operator may call a Flex Alert, usually from 4 to 9 p.m. Pre-cool your home to 72°F (22°C) in the morning, then set the thermostat to 78°F (26°C) or higher if your health allows, and run big appliances outside those hours. Sign up at flexalert.org (California ISO).
• Cut outdoor water use. About 40% of the water Californians use is used outdoors. The state’s Save Our Water campaign has a rebate finder for replacing lawns with water-wise plants (Save Our Water).
• Check the air before you go out. The AirNow Fire and Smoke Map, run by the EPA and the U.S. Forest Service, combines fire locations, smoke plumes and readings from official monitors and about 15,000 low-cost sensors (EPA).
• Compare with other places. Our overview of environmental issues in the USA covers the country as a whole, and our guide to environmental issues in Florida shows how a wetter state faces rising seas and polluted water. Across the border, our article on environmental issues in Mexico covers shared water and air problems. For a European comparison, see our article on environmental issues in Germany, and our overview of global environmental issues puts California in world context.

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